package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据

        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog -> {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    @Override
    public Result queryBlogById(Long id) {
        Blog blog=getById(id);
        if(blog==null){
            return Result.fail("博客不存在");
        }
        queryBlogUser(blog);
        //查询是否点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    private void isBlogLiked(Blog blog) {
        //1、查询当前用户
        if(UserHolder.getUser()==null){
            return;
        }
        Long userId= UserHolder.getUser().getId();

        //1、将点赞id存入redis
        String key=BLOG_LIKED_KEY+blog.getId();
        //2、判断用户id是否已存在
        Double isMember = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(isMember!=null);
    }

    @Override
    public void likeBlog(Long id) {
        Long userId= UserHolder.getUser().getId();
        //1、将点赞id存入redis
        String key=BLOG_LIKED_KEY+id;
        //2、判断用户id是否已存在
        Double isMember = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if(isMember==null){
            //3、如果不存在，则存入redis，并更新点赞数
            Boolean isSuccess=update().setSql("liked=liked+1").eq("id",id).update();
            if(isSuccess) {
                stringRedisTemplate.opsForZSet().add(key, userId.toString(), System.currentTimeMillis());
            }
        }else{
            //4、如果存在，则删除redis中的点赞数，并更新点赞数
            Boolean isSuccess=update().setSql("liked=liked-1").eq("id",id).update();
            if(isSuccess) {
                stringRedisTemplate.opsForZSet().remove(key, userId.toString());
            }

        }
        //3、如果不存在，则存入redis，并更新点赞数
        //4、如果存在，则删除redis中的点赞数，并更新点赞数

    }

    @Override
    public Result queryBlogLikes(Long id) {
        //从redis查询出前五条点赞数据
        String key=BLOG_LIKED_KEY+id;
        Set<String> top5=stringRedisTemplate.opsForZSet().range(key,0,4);
        if(top5==null||top5.isEmpty()){
            return Result.ok();
        }
        //解析出ids
        List<Long> ids= top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String str= StrUtil.join(",",ids);
        //根据ids查询用户
        List<UserDTO> users = userService.query()
                .in("id", ids)
                .last("ORDER BY FIELD(id,"+str+")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        return Result.ok(users);
    }

    @Override
    public Result saveBlog(Blog blog) {
        //获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        //保存
        boolean isSuccess= save(blog);
        if(!isSuccess){
            return Result.fail("博客新增失败");
        }
        //查询笔记作者的所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        //推送
        for (Follow follow : follows) {
            Long userId=follow.getUserId();
            String key=FEED_KEY+userId;
            stringRedisTemplate.opsForZSet().add(key, blog.getId().toString(), System.currentTimeMillis());
        }
        //返回id
        return Result.ok(blog.getId());
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1 获取当前用户
        UserDTO userDTO=UserHolder.getUser();
        long userId=userDTO.getId();
        //2 根据用户id查询收件箱
        String key=FEED_KEY+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet().
                reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        //3 获取元组后元组里村的就是当前值和时间戳
        if(typedTuples==null||typedTuples.isEmpty()){
            return Result.ok();
        }
        //4 解析数据 获取偏移量，最小时间相同量
        int os=1;
        long minTime=0L;
        List<Long> ids=new ArrayList<>(typedTuples.size());
        for(ZSetOperations.TypedTuple<String> tuple:typedTuples){
            String value = tuple.getValue();
            ids.add(Long.valueOf(value));
            long time=tuple.getScore().longValue();
            if(minTime==time){
                os++;
            }else{
                minTime=time;
                os=1;
            }
        }
        //5 根据id查询blog
        List<Blog> blogs = query().in("id", ids).
                last("ORDER BY FIELD(id," + StrUtil.join(",", ids) + ")").list();
        //6 封装blog查询用户,设置头像和点赞数
        for (Blog blog : blogs) {
            queryBlogUser(blog);
            isBlogLiked(blog);
        }
        //7 封装返回结果
        ScrollResult scrollResult=new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setOffset(os);
        scrollResult.setMinTime(minTime);
        return Result.ok(scrollResult);
    }
}
